The essential American soul is hard, isolate, stoic, and a killer. It has never yet melted. — D.H. Lawrence

The Telegraph reports that al-Qaeda’s American-born propaganda chief has been silent for so long that Western intelligence sources are concluding he’s gone to ask Allah for his virgins.

Months of attacks by unmanned US predator aircraft have caused carnage among the middle ranks of terrorist leaders in the lawless lands along the border with Afghanistan, where al-Qa’eda remains dangerous despite suffering a serious defeat in Iraq.

Their victims have included experienced Arab leaders and, it is now thought, Adam Gadahn, a former heavy-metal fan and so-called “killer computer nerd” originally from California. Nothing has been heard from him for months, leading intelligence experts to conclude that he may be dead.

Mr Gadahn has been credited with helping transform al-Qa’eda’s al-Sahab propaganda wing into a slick operation which communicates in fluent English and produces professional quality DVDs, including one for Osama bin Laden last year.

But he may have fallen victim to an expanded programme of predator assassinations which in the last year has targeted and killed many of al-Qa’eda’s military commanders, terrorist trainers and facilitators.

Jihadists around the world will be watching as closely as intelligence officials this week to see whether Mr Gadahn – also known as Azzam al-Ameriki – produces a new video message to mark September 11, as he has done every year since 2003.

If there is no message it will be taken as near certain confirmation that he is dead – killed either in a strike by Hellfire missiles, or perhaps by jihadi colleagues who have grown jealous of his success.

Mr Gadahn is now thought to have been killed in an attack launched from a remotely piloted aircraft in January which killed al-Qaeda’s then military commander, Abu Laith al-Libi, in Mir Ali, Waziristan. …

Gadahn has taken on real importance as al-Qa’eda’s best known Westerner. He also became the poster boy of would-be jihadis around the world who are radicalised on the internet – and identify with a former Orange County teenager who once reviewed heavy metal bands before finding radical Islam and travelling to Pakistan in 1998.